Word Document Properties

Chapter 8: Object-Oriented Programming
14_046500 ch08.qxp 12/5/06 5:36 PM Page 191

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Listing 8-2 
(continued)
‘ the user about the problem.
Err.Raise vbObjectError + 1, _
“SpecialMsg.Show”, _
“You must provide a HelpFilename “ +
_
“property value to use the Help “ +
_
“button in a message box.”
Else
‘ The user has provided all required help
‘ information, so set the help button option.
Options = Options Or vbMsgBoxHelpButton
End If
End If
‘ Determine if the message box will display help.
If ((TheHelpFile = “”) And (Not UseHelpButton)) Then
‘ Display a message box without help.
Result = MsgBox(ThePrompt, Options, TheTitle)
Else
‘ Display a message box that includes help.
Result = MsgBox(ThePrompt, Options, TheTitle, _
TheHelpFile, TheHelpContext)
End If
‘ Raise the Click event so the caller can react to it.
RaiseEvent Click(Result)
‘ Return a result.
Show = Result
End Function
The 
MsgBox
function provides access to a number of styles. It’s easy to
forget how many styles until you start looking at code like this. The code 
creates an 
Options
variable that contains all the style options that you’ve
set up through object properties. It selects an icon, a button set, a default
button, and a modality type (application or system). These options always
appear in the list, and the 
Class_Initialize
method sets them to default
values. (See the upcoming “Defining initialization” section for details.) The
Options
variable can also contain a number of optional settings. The code
checks the Boolean values, such as 
UseForeground
, to determine whether
you want to include these optional styles. It then adds the actual style to the
Options
variable.
Notice that the 
UseHelpButton If...Then
statement includes error 
handling. See the upcoming “Adding Error Handling to Classes” section for a
description of class error handling. In this case, the class determines whether
you’ve assigned a help file to the message object. If not, clicking the Help
button causes an error. The 
MsgBox
function doesn’t protect you from this
error, but the 
SpecialMsg
class does.
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